Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely non-redundant behavior: per-call pricing (¥0.2), charge-on-success-only, and automatic refund on failure or empty result — material for an agent deciding whether to retry or batch.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three compact sentences ordered well: what it does, what it returns, when to use it, then the cost model. No filler, though the return-field list and the pricing sentence compete for the same short space and could be trimmed slightly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, and the description compensates by enumerating the returned fields (caption, like/comment counts, author info, media list, publish time). Combined with the prerequisite framing and the billing rules, an agent has everything needed to call it correctly and to budget for it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%: the schema documents both 'shortcode' and the backup '_token' auth with the recommendation to use the X-FW-Token header instead. The description only implies that the shortcode is an Instagram post identifier and adds no format detail (raw code vs. full URL), so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource pair ('shortcode转media_id') and adds the role it plays ('评论接口前置'), so the agent knows this is an ID-resolution step rather than a content fetch. It stops short of explicitly naming the sibling it differs from (e.g. ig_post_detail or ig_post_comments), which is the only thing keeping it from a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives concrete use contexts: single-post engagement analysis, material archiving, and as the starting point of a batch job, plus the workflow hint that it precedes the comment endpoints. It does not state when NOT to use it or name the alternative tool that would replace it, so it is clear context without exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.